2 resultados para Scale Invariance
em DigitalCommons@The Texas Medical Center
Resumo:
In the last thirty years, increasing efforts have been made to reduce the prevalence of adolescent tobacco use in the United States. Although the prevalence has declined dramatically over the past decade, there are still sharp differences in adolescent smoking-initiation rates across racial/ethnic groups. Large-scale surveys frequently assess smoking-related attitudes, self-efficacy, and intentions to explain the differences in smoking rates between African Americans and Whites. However, there is little agreement about which constructs are significant. Moreover, the psychometric properties of smoking-related attitude, self-efficacy, and intention constructs have not been fully examined. More studies are needed to understand existing patterns of tobacco use and to validate and fully exploit the constructs' relationship to adolescent smoking initiation across racial/ethnic groups. ^ This dissertation reports on a secondary analysis of data from a large multi-ethnic convenience sample of sixth- through eighth-grade students in 22 schools in East Texas and the city of Houston. The specific aims of this dissertation were to (1) describe smoking and alternate tobacco product use rates by race/ethnicity, gender, age, and grade level (Article 1); (2) test the factorial validity of smoking-related attitudes, self-efficacy, and intentions using confirmatory factor analysis techniques (Article 2); and (3) test the factorial invariance of smoking-related attitudes, self-efficacy, and intentions between African Americans and Whites (Article 3). ^ The prevalence findings confirm the disparities in tobacco use among African American, Hispanic, and White adolescents that other surveys have reported (Article 1). This study also demonstrates the usefulness of examining use patterns of not only cigarettes but also alternative tobacco products in younger multiethnic populations, as well as of providing epidemiological data estimates about different phases of smoking. The confirmatory factor analysis provides evidence of construct validity of attitude, self-efficacy, and intention scales for the multiethnic sample (Article 2). Finally, the factorial invariance analyses indicates that some measures representing smoking-related attitudes, self-efficacy, and intentions may not be appropriate for use among both African Americans and Whites (Article 3). Additional research is needed to further our understanding of the patterns and predictors of youth tobacco use initiation. ^
Resumo:
Background. At present, prostate cancer screening (PCS) guidelines require a discussion of risks, benefits, alternatives, and personal values, making decision aids an important tool to help convey information and to help clarify values. Objective: The overall goal of this study is to provide evidence of the reliability and validity of a PCS anxiety measure and the Decisional Conflict Scale (DCS). Methods. Using data from a randomized, controlled PCS decision aid trial that measured PCS anxiety at baseline and DCS at baseline (T0) and at two-weeks (T2), four psychometric properties were assessed: (1) internal consistency reliability, indicated by factor analysis intraclass correlations and Cronbach's α; (2) construct validity, indicated by patterns of Pearson correlations among subscales; (3) discriminant validity, indicated by the measure's ability to discriminate between undecided men and those with a definite screening intention; and (4) factor validity and invariance using confirmatory factor analyses (CFA). Results. The PCS anxiety measure had adequate internal consistency reliability and good construct and discriminant validity. CFAs indicated that the 3-factor model did not have adequate fit. CFAs for a general PCS anxiety measure and a PSA anxiety measure indicated adequate fit. The general PCS anxiety measure was invariant across clinics. The DCS had adequate internal consistency reliability except for the support subscale and had adequate discriminate validity. Good construct validity was found at the private clinic, but was only found for the feeling informed subscale at the public clinic. The traditional DCS did not have adequate fit at T0 or at T2. The alternative DCS had adequate fit at T0 but was not identified at T2. Factor loadings indicated that two subscales, feeling informed and feeling clear about values, were not distinct factors. Conclusions. Our general PCS anxiety measure can be used in PCS decision aid studies. The alternative DCS may be appropriate for men eligible for PCS. Implications: More emphasis needs to be placed on the development of PCS anxiety items relating to testing procedures. We recommend that the two DCS versions be validated in other samples of men eligible for PCS and in other health care decisions that involve uncertainty. ^